This invention relates to a golf club head of the type in which a sole plate is prevented from dislodgment.
Recently, in view of the stability of quality, the ease of supply of materials and so on, metal golf club heads (called "wood"), in which a head body of a hollow construction is cast of metal such as stainless steel and an aluminum alloy, have been extensively used instead of golf club heads made of natural wood such as persimmon and cherry. Metal has a higher strength than wood, and therefore when a head body is thus cast into a hollow construction so that the weight is distributed over a peripheral portion of the head, a moment of inertia increases, thereby achieving a directional stability of a ball.
In order to increase a repulsive coefficient at the time of hitting a ball to thereby secure a flying distance, it has been proposed to mount a face plate of a fiber-reinforced resin onto a face portion of a head body. In order to adjust the weight of a golf club head, it has been proposed to mount a sole plate, cast of metal greater in specific gravity than a head body, onto a sole portion to thereby lower the center of gravity of the head. These and other measures have been adopted.
One conventional method of securing a sole plate, made of metal different from that of a metal head body, to the metal head body is to bond them together by an epoxy adhesive. In another conventional method as disclosed in Japanese Patent Unexamined Patent Publication No. 6-23070 and shown in FIG. 4, a sole plate 3, having a retaining portion 1, is integrally connected to a head body 5 to close a bottom opening in the head body 5 when casting the head body 5 of metal lower in melting point than the sole plate 3.
However, in the construction of bonding the sole plate by the adhesive, an adequate bonding strength can not be obtained, thus posing a problem with respect to durability. In the mounting construction shown in FIG. 4, the sole plate 3 and the head body 5 are merely engaged with each other through the recess and protrusion at the peripheral edge of the sole plate 3, and therefore when the sole plate 3 is caused to strike against the ground at the time of hitting a ball, there is a possibility that the sole plate 3 is dislodged into the hollow head body 5.
Japanese Patent Unexamined Publication No. 63-264085 discloses a golf head club 13 (see FIG. 5) in which a wall portion 9 of a cross shape in section is formed integrally within a hollow metal head body 7 by casting, and extends between a toe and a heel, between a face and a back, and between a top and a sole. This wall portion 9 divides the interior of the head body into four hollow chambers 11.
Assuming that this wall portion 9 is provided to serve as a reinforcement member for the sole plate, the sole plate 3 will not be dislodged into the hollow head body 7 even when the sole plate 3 is caused to strike against the ground at the time of hitting a ball.
However, in the case where the wall portion 9 is thus formed over a region between the top and the sole, the golf club head 13 has a high center of gravity, and this invites a drawback that it is difficult to easily hit a ball with this golf club.